C# Interactive and Entity Framework

Question

I am trying to run a method in C# Interactive that return some data from local db using Entity Framework. But it return an error saying that the connection string named 'InteractiveConsoleDBEntities' could be found in the application config file. I am using data base first. I use the option "Initialize Interactive with project" to start with C# Interactive.

Here is the details...

Commands in Interactive Console

#r "C:\Users\Path\InteractiveConsole\packages\EntityFramework.5.0.0\lib\net45\EntityFramework.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.ComponentModel.DataAnnotations.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Core.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Data.Entity.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Runtime.Serialization.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Security.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Xml.Linq.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Data.DataSetExtensions.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\Microsoft.CSharp.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Data.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Net.Http.dll"
#r "C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.1\System.Xml.dll"
#r "InteractiveConsole.exe"
using InteractiveConsole;
using InteractiveConsole.Model;
using InteractiveConsole.DAL;
var context = new InteractiveConsoleDBEntities();
context.Employees.ToList();

Then I get the error

No connection string named 'InteractiveConsoleDBEntities' could be found in the application config file.
  + System.Data.Entity.Internal.LazyInternalConnection.get_ConnectionHasModel()
  + System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
  + System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(System.Type)
  + InternalSet<TEntity>.Initialize()
  + InternalSet<TEntity>.Include(string)
  + DbQuery<TResult>.Include(string)
  + System.Data.Entity.DbExtensions.Include<T>(IQueryable<T>, string)
  + System.Data.Entity.DbExtensions.Include<T, TProperty>(IQueryable<T>, Expression<Func<T, TProperty>>)
  + InteractiveConsole.DAL.EmployeeDAL.GetEmployeeList()

The App.config file

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
  </startup>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v13.0" />
      </parameters>
    </defaultConnectionFactory>
  </entityFramework>
  <connectionStrings>
    <add name="InteractiveConsoleDBEntities" connectionString="metadata=res://*/Model.Model.csdl|res://*/Model.Model.ssdl|res://*/Model.Model.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=(LocalDB)\MSSQLLocalDB;attachdbfilename=|DataDirectory|\DB\InteractiveConsoleDB.mdf;integrated security=True;connect timeout=30;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
</configuration>

The DbContext

namespace InteractiveConsole.Model
{
    using System;
    using System.Data.Entity;
    using System.Data.Entity.Infrastructure;

    public partial class InteractiveConsoleDBEntities : DbContext
    {
        public InteractiveConsoleDBEntities()
            : base("name=InteractiveConsoleDBEntities")
        {

        }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            throw new UnintentionalCodeFirstException();
        }

        public DbSet<Employee> Employees { get; set; }
        public DbSet<Person> People { get; set; }
    }
}

The class with method

using System.Data.Entity;

namespace InteractiveConsole.DAL
{
    public class EmployeeDAL
    {
        public static List<Employee> GetEmployeeList()
        {
            using (var context = new InteractiveConsoleDBEntities())
            {
                return context.Employees.Include(x => x.Person).ToList();
            }
        }
    }
}

The same project in Immediate Window works fine

InteractiveConsole.DAL.EmployeeDAL.GetEmployeeList()
Count = 2
    [0]: {System.Data.Entity.DynamicProxies.Employee_0D99EB301BB74EDFF2203163D6E8A936C70F24995F1639BF58D81DCCA671DEC0}
    [1]: {System.Data.Entity.DynamicProxies.Employee_0D99EB301BB74EDFF2203163D6E8A936C70F24995F1639BF58D81DCCA671DEC0}

Hope some one know what I doing wrong and can help me.

Thanks a lot

Answer 1

Struggled with this one for a while before I finally got it working.

Create a new partial class (for example named YourEntities.cs) with a new overload for your constructor that takes a connection string parameter (don't modify your existing class as it will be overwritten whenever you re-model the database):

using System.Data.Entity;

namespace YourNamespace.Models
{
    public partial class YourEntities : DbContext
    {
        public YourEntities(string connectionString)
            : base(connectionString)
        {
        }
    }
}

Then, build your project, right click it and click "Initialize Interactive with Project". Open your web.config / app.config and copy the connection string to your clipboard.

In the interactive window, paste this replacing ConnStringHere with your connection string but don't hit enter:

var db = new YourNamespace.Models.YourEntities("ConnStringHere");

After you paste, replace " in the connection string with \" , go to the end of the line in C# interactive and hit enter.

Then you should be able to use db in your C# Interactive window it as if it were in your app:

Print(db.Employees.Count());

Answer 2

I realize this is old, but I found a way to make this work without changing my code, or creating any proxies or other work-around code. I was able to make this work by editing the config file for the interactive window, itself. See my answer in this post:

Project can't find my EF connection string in C# Interactive

You may have to add other config data, as well, if your app relies on it. Just adding the connection string was enough, for me.